You and a friend are going to ride on a Ferris wheel. For a little extra fun, when your friend is at the very top of the Ferris wheel she's going to drop a tennis ball. How far around the Ferris wheel in radians from your friend should you sit so you can catch the ball?

Details and assumptions
The Ferris wheel radius is R=20 m.
The Ferris wheel goes around at a constant angular velocity ω=0.2 rad/s.
The acceleration of gravity is −9.8 m/s2.
Neglect air resistance.